Why does my libGDX resize code break camera.unproject?

Question

I'm using the following code in my resize method to maintain aspect ratio across multiple screen sizes:

@Override
public void resize(int width, int height)
{
    float aspectRatio = (float)width / (float)height;
    float scale = 1f;
    Vector2 crop = new Vector2(0, 0);

    if (aspectRatio > globals.ASPECT_RATIO)
    {
        scale = (float)height / (float)globals.VIRTUAL_HEIGHT;
        crop.x = (width - globals.VIRTUAL_WIDTH * scale) / 2f;
    }
    else if (aspectRatio < globals.ASPECT_RATIO)
    {
        scale = (float)width / (float)globals.VIRTUAL_WIDTH;
        crop.y = (height - globals.VIRTUAL_HEIGHT * scale) / 2f;
    }
    else
    {
        scale = (float)width / (float)globals.VIRTUAL_WIDTH;
    }

    float w = (float)globals.VIRTUAL_WIDTH * scale;
    float h = (float)globals.VIRTUAL_HEIGHT * scale;

    viewport = new Rectangle(crop.x, crop.y, w, h);
}

VIRTUAL_WIDTH, VIRTUAL_HEIGHT and ASPECT_RATIO are set as follows:

public final int VIRTUAL_WIDTH = 800;
public final int VIRTUAL_HEIGHT = 480;
public final float ASPECT_RATIO = (float)VIRTUAL_WIDTH / (float)VIRTUAL_HEIGHT;

This works perfectly with regards to maintaining the correct ratio when the screen size changes. However, camera.uproject (which I call before all touch events) doesn't work properly - touch positions are not correct when the resize code changes the screen size to anything other than 800x480.

Here's how I setup my camera in my create() method:

camera = new OrthographicCamera(globals.VIRTUAL_WIDTH, globals.VIRTUAL_HEIGHT);
camera.setToOrtho(true, globals.VIRTUAL_WIDTH, globals.VIRTUAL_HEIGHT);

And this is the start of my render() method:

camera.update();
Gdx.graphics.getGL20().glViewport((int)viewport.x, (int)viewport.y, 
(int)viewport.width, (int)viewport.height);
Gdx.graphics.getGL20().glClearColor(0, 0, 0, 1);
Gdx.graphics.getGL20().glClear(GL20.GL_COLOR_BUFFER_BIT);

If I ignore the resize code and set the glViewport method call to Gdx.graphics.getWidth() and Gdx.graphics.getHeight(), camera.unproject works, but I obviously lose the maintaining of the aspect ratio. Anyone have any ideas?

Here's how I perform the unproject on my touch events:

private Vector3 touchPos = new Vector3(0, 0, 0);

public boolean touchDown (int x, int y, int pointer, int newParam)
{
    touchPos.x = x;
    touchPos.y = y;
    touchPos.z = 0; 
    camera.unproject(touchPos);

    //touch event handling goes here...
}

UPDATE

I've made a little more progress with this by implementing a Stage object, but it's still not working perfectly.

Here's how I now setup the stage and camera in my create method:

stage = new Stage();
camera = new OrthographicCamera(globals.VIRTUAL_WIDTH, globals.VIRTUAL_HEIGHT);
camera.setToOrtho(true, globals.VIRTUAL_WIDTH, globals.VIRTUAL_HEIGHT);
stage.setCamera(camera);

Here's my resize code:

public void resize(int width, int height)
{
    Vector2 size = Scaling.fit.apply(800, 480, width, height);
    int viewportX = (int)(width - size.x) / 2;
    int viewportY = (int)(height - size.y) / 2;
    int viewportWidth = (int)size.x;
    int viewportHeight = (int)size.y;
    Gdx.gl.glViewport(viewportX, viewportY, viewportWidth, viewportHeight);
    stage.setViewport(800, 480, true, viewportX, viewportY, viewportWidth, viewportHeight);
}

Here's the start of my render code:

stage.getCamera().update();
Gdx.graphics.getGL20().glClearColor(0, 0, 0, 1);
Gdx.graphics.getGL20().glClear(GL20.GL_COLOR_BUFFER_BIT);
spriteBatch.setProjectionMatrix(stage.getCamera().combined);

And here's how I handle touch events:

private Vector3 touchPos = new Vector3(0, 0, 0);

public boolean touchDown (int x, int y, int pointer, int newParam)
{
    touchPos.x = x;
    touchPos.y = y;
    touchPos.z = 0;
    stage.getCamera().unproject(touchPos);

    //touch event handling goes here...
}

This now works when the screen is at default size and when the screen is enlarged. However, when the screen size is reduced the touch points become more and more inaccurate the smaller the screen gets.

Answer 1

Managed to find the answer to this. I simply needed to use the camera.unproject method call which takes Vector3, viewportX, viewportY, viewportWidth and viewportHeight parameters. The required viewport params are those calculated by the resize code shown above.

Answer 2

To solve your issue there is already a implemented solution inside of the new Stage system. Please take a look at the wiki scene2d #viewport. To have a fixed aspec ratio you do not need to resize and fit in manually. Here is the example with blackbars from the wiki:

public void resize (int width, int height) {
        Vector2 size = Scaling.fit.apply(800, 480, width, height);
        int viewportX = (int)(width - size.x) / 2;
        int viewportY = (int)(height - size.y) / 2;
        int viewportWidth = (int)size.x;
        int viewportHeight = (int)size.y;
        Gdx.gl.glViewport(viewportX, viewportY, viewportWidth, viewportHeight);
        stage.setViewport(800, 480, true, viewportX, viewportY, viewportWidth, viewportHeight);
}